platform_system_core/init/mount_namespace.h

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Proper mount namespace configuration for bionic This CL fixes the design problem of the previous mechanism for providing the bootstrap bionic and the runtime bionic to the same path. Previously, bootstrap bionic was self-bind-mounted; i.e. /system/bin/libc.so is bind-mounted to itself. And the runtime bionic was bind-mounted on top of the bootstrap bionic. This has not only caused problems like `adb sync` not working(b/122737045), but also is quite difficult to understand due to the double-and-self mounting. This is the new design: Most importantly, these four are all distinct: 1) bootstrap bionic (/system/lib/bootstrap/libc.so) 2) runtime bionic (/apex/com.android.runtime/lib/bionic/libc.so) 3) mount point for 1) and 2) (/bionic/lib/libc.so) 4) symlink for 3) (/system/lib/libc.so -> /bionic/lib/libc.so) Inside the mount namespace of the pre-apexd processes, 1) is bind-mounted to 3). Likewise, inside the mount namespace of the post-apexd processes, 2) is bind-mounted to 3). In other words, there is no self-mount, and no double-mount. Another change is that mount points are under /bionic and the legacy paths become symlinks to the mount points. This is to make sure that there is no bind mounts under /system, which is breaking some apps. Finally, code for creating mount namespaces, mounting bionic, etc are refactored to mount_namespace.cpp Bug: 120266448 Bug: 123275379 Test: m, device boots, adb sync/push/pull works, especially with following paths: /bionic/lib64/libc.so /bionic/bin/linker64 /system/lib64/bootstrap/libc.so /system/bin/bootstrap/linker64 Change-Id: Icdfbdcc1efca540ac854d4df79e07ee61fca559f
2019-01-16 15:00:59 +01:00
/*
* Copyright (C) 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <android-base/result.h>
Proper mount namespace configuration for bionic This CL fixes the design problem of the previous mechanism for providing the bootstrap bionic and the runtime bionic to the same path. Previously, bootstrap bionic was self-bind-mounted; i.e. /system/bin/libc.so is bind-mounted to itself. And the runtime bionic was bind-mounted on top of the bootstrap bionic. This has not only caused problems like `adb sync` not working(b/122737045), but also is quite difficult to understand due to the double-and-self mounting. This is the new design: Most importantly, these four are all distinct: 1) bootstrap bionic (/system/lib/bootstrap/libc.so) 2) runtime bionic (/apex/com.android.runtime/lib/bionic/libc.so) 3) mount point for 1) and 2) (/bionic/lib/libc.so) 4) symlink for 3) (/system/lib/libc.so -> /bionic/lib/libc.so) Inside the mount namespace of the pre-apexd processes, 1) is bind-mounted to 3). Likewise, inside the mount namespace of the post-apexd processes, 2) is bind-mounted to 3). In other words, there is no self-mount, and no double-mount. Another change is that mount points are under /bionic and the legacy paths become symlinks to the mount points. This is to make sure that there is no bind mounts under /system, which is breaking some apps. Finally, code for creating mount namespaces, mounting bionic, etc are refactored to mount_namespace.cpp Bug: 120266448 Bug: 123275379 Test: m, device boots, adb sync/push/pull works, especially with following paths: /bionic/lib64/libc.so /bionic/bin/linker64 /system/lib64/bootstrap/libc.so /system/bin/bootstrap/linker64 Change-Id: Icdfbdcc1efca540ac854d4df79e07ee61fca559f
2019-01-16 15:00:59 +01:00
namespace android {
namespace init {
enum MountNamespace { NS_BOOTSTRAP, NS_DEFAULT };
Proper mount namespace configuration for bionic This CL fixes the design problem of the previous mechanism for providing the bootstrap bionic and the runtime bionic to the same path. Previously, bootstrap bionic was self-bind-mounted; i.e. /system/bin/libc.so is bind-mounted to itself. And the runtime bionic was bind-mounted on top of the bootstrap bionic. This has not only caused problems like `adb sync` not working(b/122737045), but also is quite difficult to understand due to the double-and-self mounting. This is the new design: Most importantly, these four are all distinct: 1) bootstrap bionic (/system/lib/bootstrap/libc.so) 2) runtime bionic (/apex/com.android.runtime/lib/bionic/libc.so) 3) mount point for 1) and 2) (/bionic/lib/libc.so) 4) symlink for 3) (/system/lib/libc.so -> /bionic/lib/libc.so) Inside the mount namespace of the pre-apexd processes, 1) is bind-mounted to 3). Likewise, inside the mount namespace of the post-apexd processes, 2) is bind-mounted to 3). In other words, there is no self-mount, and no double-mount. Another change is that mount points are under /bionic and the legacy paths become symlinks to the mount points. This is to make sure that there is no bind mounts under /system, which is breaking some apps. Finally, code for creating mount namespaces, mounting bionic, etc are refactored to mount_namespace.cpp Bug: 120266448 Bug: 123275379 Test: m, device boots, adb sync/push/pull works, especially with following paths: /bionic/lib64/libc.so /bionic/bin/linker64 /system/lib64/bootstrap/libc.so /system/bin/bootstrap/linker64 Change-Id: Icdfbdcc1efca540ac854d4df79e07ee61fca559f
2019-01-16 15:00:59 +01:00
bool SetupMountNamespaces();
base::Result<void> SwitchToMountNamespaceIfNeeded(MountNamespace target_mount_namespace);
Proper mount namespace configuration for bionic This CL fixes the design problem of the previous mechanism for providing the bootstrap bionic and the runtime bionic to the same path. Previously, bootstrap bionic was self-bind-mounted; i.e. /system/bin/libc.so is bind-mounted to itself. And the runtime bionic was bind-mounted on top of the bootstrap bionic. This has not only caused problems like `adb sync` not working(b/122737045), but also is quite difficult to understand due to the double-and-self mounting. This is the new design: Most importantly, these four are all distinct: 1) bootstrap bionic (/system/lib/bootstrap/libc.so) 2) runtime bionic (/apex/com.android.runtime/lib/bionic/libc.so) 3) mount point for 1) and 2) (/bionic/lib/libc.so) 4) symlink for 3) (/system/lib/libc.so -> /bionic/lib/libc.so) Inside the mount namespace of the pre-apexd processes, 1) is bind-mounted to 3). Likewise, inside the mount namespace of the post-apexd processes, 2) is bind-mounted to 3). In other words, there is no self-mount, and no double-mount. Another change is that mount points are under /bionic and the legacy paths become symlinks to the mount points. This is to make sure that there is no bind mounts under /system, which is breaking some apps. Finally, code for creating mount namespaces, mounting bionic, etc are refactored to mount_namespace.cpp Bug: 120266448 Bug: 123275379 Test: m, device boots, adb sync/push/pull works, especially with following paths: /bionic/lib64/libc.so /bionic/bin/linker64 /system/lib64/bootstrap/libc.so /system/bin/bootstrap/linker64 Change-Id: Icdfbdcc1efca540ac854d4df79e07ee61fca559f
2019-01-16 15:00:59 +01:00
} // namespace init
} // namespace android